Energy absorbing steering assembly

ABSTRACT

An energy absorbing steering assembly for a motor vehicle having a steering column supporting assembly for supporting the steering column substantially at a right angle from the instrument panel of the vehicle and a steering wheel supporting assembly being able to forwardly deflect. The steering column supporting assembly is enabled to buckle to absorb forward impact energy when an impact force is exerted onto the steering wheel and the steering wheel supporting assembly functions to absorb further the forward impact energy in addition to the buckling operation of the steering column supporting assembly.

This is a division of application Ser. No. 256,872, filed May 25, 1972,now U.S. Pat. No. 3,822,608.

BACKGROUND OF THE INVENTION

The present invention relates generally to vehicle steering assembliesand more particularly, to the type of steering column construction thatis enabled to absorb forward impact energy by controlled deflection ofthe steering column components and the steering wheel assembly inoccurrence of a vehicle collision.

To protect a motor vehicle driver in occurrence of a collision, therehave been introduced various types of safety apparatus for steeringassemblies. In the prior art devices, however, the safety feature israther limited to local deformation of the steering wheel or to an axialdeflection of the steering column, which is never enough to expectdesired safety effects for the drivers, particularly, for certain typesof vehicles. This has particularly been true for the drivers of tracksof cab-over type and buses the steering shafts of which are rathervertically provided to have the steering wheels positioned angularlytoward the driver's bodies. Thus, the sharp angle of the impact loadgiven to the drivers has resulted in serious damages against thedrivers.

It should well be considered to be very ideal for the mentioned certaintypes of vehicles, if the drivers are protected by total impact energyabsorbing operation obtained through enough deflective displacements ofthe steering column as well as the steering wheel.

BRIEF SUMMARY OF THE INVENTION

It is, therefore, a prime object of the present invention to provide asafety apparatus most properly designed for a steering column assemblywhich includes a steering shaft connected vertically with the vehiclesteering gear by way of a flexible coupling to be forwardly deflectiveand a column tube having the steering shaft journalled rotatablytherein.

It is another object of the present invention to provide a safetyapparatus, having the above mentioned characteristics, wherein asteering column supporting assembly supports the steering columnassembly substantially at a right angle from an instrument panel of avehicle and is enabled to buckle to absorb forward impact energy when animpact force is exerted onto the upper portion of the steering column.

It is another object of the present invention to provide a saftyapparatus, having the above mentioned characteristics, wherein thesteering column supporting assembly functions to guide the displacingdirection of the steering column when an impact force is exerted ontothe upper portion of the steering column.

It is a further object to provide a safety apparatus, having the abovementioned characteristics, wherein a steering wheel supporting assemblyis enabled to deflect to absorb further the forward impact energy inaddition to the functions of the steering column supporting assembly.

It is still another object of the present invention to provide a safetyapparatus, having the above mentioned characteristics, in which thesafety apparatus can be manufactured compactly with a low productioncost and be installed in the vehicle with simple assembling, theapparatus yet being durable and ensuring accurate operation thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more readily apparent from the followingdescription of the preferred embodiments with reference to theaccompanying drawings forming a part of the specification.

In the drawings:

FIG. 1 is a side view of a cab-over type motor vehicle which adopts thepresent invention.

FIG. 2 is a side view of the steering column device of the motor vehiclein FIG. 1.

FIG. 3 shows a partial sectional-plane view of a first embodiment inaccordance with the present invention.

FIG. 4 is an elevational sectional view taken along A--A line in FIG. 3.

FIG. 5 is a partially enlarged view of the column stay shown in FIG. 4.

FIG. 6 includes FIGS. 6-A and 6-B; FIG. 6-A illustrates across-sectional view taken along B--B line in FIG. 3 and FIG. 6-B showsa modification of FIG. 6-A.

FIG. 7 illustrates a partial sectional-plane view of a second embodimentin accordance with the present invention.

FIG. 8 is an elevational sectional view taken along C--C line in FIG. 7.

FIG. 9 shows a partial sectional-plane view of a third embodiment inaccordance with the present invention.

FIG. 10 is an elevational sectional view taken along D--D line in FIG.9.

FIG. 11 is a side view taken along an arrow in FIG. 10.

FIG. 12 includes FIG. 12-A and FIG. 12-B and shows a partialsectional-plane view of a fourth embodiment in accordance with thepresent invention. FIG. 12-B shows a modification of FIG. 12-A.

FIG. 13 shows an elevational sectional view taken along E--E line inFIG. 12.

FIG. 14 shows a partial sectional-plane view of a fifth embodiment inaccordance with the present invention.

FIG. 15 is an elevational sectional view taken along F--F in FIG. 14.

FIG. 16 is a partial sectional-plane view of a sixth embodiment inaccordance with the present invention.

FIG. 17 is an elevational sectional view taken along G--G line in FIG.16.

FIG. 18 shows an elevational section of a steering wheel devicecharacterized with another feature of the present invention.

FIG. 19 shows the steering wheel device shown in FIG. 18 whendeflectively displaced.

FIG. 20 shows a partially enlarged sectional-plane view of the steeringwheel device in FIG. 18.

FIG. 21 is an enlarged elevational sectional view taken along H--H linein FIG. 20.

FIG. 22 is a perspective view of a supporting member to support spokesshown in FIGS. 18-21, inclusive.

FIG. 23 is a perspective view of a hub fixed on the steering shaft shownin FIGS. 18-21, inclusive.

FIG. 24 shows an elevational sectional view of a modification of thesteering wheel device shown FIG. 18.

FIG. 25 is a front view of an energy absorbing member which is animportant construction member of the device shown in FIG. 24.

FIG. 26 is a cross-sectional view taken along J--J line in FIG. 25.

FIG. 27 shows a front view of a modification of the energy absorbingmember in FIG. 25.

FIG. 28 shows a cross-sectional view taken along K--K line in FIG. 27.

FIG. 29 shows a front view of another modification of the energyabsorbing member in FIG. 25.

FIG. 30 is a cross-sectional view taken along L--L line in FIG. 29.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is particularly made to FIGS. 1 and 2 wherein there is shown asteering column 10 including a column tube 12, a steering shaft 11rotatably coupled within the column tube 12 and connected to the vehiclesteering gear 14 through a flexible coupling 13, and a flexible cover 17having the column 12 and steering shaft 11 engaged therein and coveringup a fire wall 18. A steering wheel 16 is mounted on the upper end ofthe steering shaft 11 and a steering column cover 15 is installed at theupper end of the column tube 12. An energy absorbing device S featuresthe most important portion of the present invention. The steering column10 is supported on an instrument panel 80, which is a portion of thevehicle body, through the energy absorbing device S. In energy absorbingoperation, the whole steering assembly is deflected to a forwardposition shown with dotted lines.

Disclosed hereinafter are several preferred embodiments of the presentinvention. To avoid unnecessary confusion, same and similar referencenumerals are applied for the same and similar parts throughout all theembodiments.

FIGS. 3 to 6, inclusive, are for a first preferred embodiment of thepresent invention. The energy absorbing device S comprises a column stay20 for holding the column tube 12 substantially at a right angle againstthe instrument panel 80 and a guide pin 31 for guiding the column stay20 in its forward movement by a predetermined or more force loading in aforward direction on the upper portion of the steering column 10. Asbest shown in FIG. 3, the column stay 20 is formed in a substantialV-shape and provided with a pair of inner reinforcement flanges 21a and21b jutting downwardly in parallel from the inner edge thereof and anouter reinforcement flange 22 extending downwardly from the outer edgethereof. The inner flanges 21a and 21b have respectively longitudinallytapered slits 210a and 210b positioned correspondingly with each otherand substantially at a right angle toward the steering column 10. Theslits 210a and 210b are provided at both ends thereof respectively withholes 211a, 211b and with 212a and 212b.

It may not be indispensable that the slits 210a and 210b are formed inthe longitudinally tapered shape. They may be straight or of an arc, or,furthermore, as well shown in FIG. 6-A, are covered with synthetic resin31b. A pair of capsules 23, one of them only being shown in FIGS. 3 and4, has recesses 23a, 23a thereon engaged loosely in the side edges 20a,20b of the column stay 20. Synthetic resin 24, for instanceexpoxy-resin, is filled in spaces between the column stay 20 and thecapsule 23 to form a shearable connection so that the column stay 20 mayslidably move with the predetermined or more impact load exertedthereon. A bolt 34 is inserted into a through hole 23b of the capsule 23through a spring washer 35 and threaded into a nut 36 welded on theupper face of the lower portion of the instrument panel 80. Thus, thecolumn stay 20 is releasably fastened onto the instrument panel 80together with a bracket 32.

As shown in FIGS. 3 and 4, the right end portion of the column stay 20and a clamping member 27 incorporate to hold the column tube 12therebetween through a cylindrical spacer 26 made of such elasticmaterials as rubber, synthetic resin and the like. The clamping member27 is fastened onto the outer flange 22 of the column stay 20 by way ofa bolt 28a threaded through a spring washer 29 into a nut 28b welded onthe inner face of the outer flange 22. It should be clear here that thecolumn tube 12 is firmly supported in its normal position.

The guide pin 31 is welded on a strut 33 welded on the central portionof the bottom side of the bracket 32 fastened on the instrument panel 80together with the capsule 23. The strut 33 has a substantial U-shapesection and is interposed between the pair of inner flanges 21a and 21b.Grooves 33a provided on the both ends of the guide pin 31 are looselyengaged in te holes 211a and 212a of the inner flanges 21a and 21b. Thesaid grooves 33a of the guide pin 31 are to secure the moving directionof the column stay 20 when the column stay 20 moves forward by operationdescribed hereinafter. The grooves 33a may be replaced with guide ringsand the like.

With the above-mentioned steering column 10 constructed in accordancewith the present invention, an impact load exerted to the steering wheel16 through a driver in occurrence of a collision of the vehicle istransmitted to the column stay 20 holding the steering column 10. Thetransmitted load breaks the shearable connection between the capsule 23and the column stay 20 to cause a forward movement of the column stay 20at the bottom side of the instrument panel 80. As the column stay 20moves fowardly, the slits 210a and 210b of the inner flanges 21a and 21bare gradually and slidably pushed forward to be expanded, the movementof the slits 210a and 210b being guided by the grooves 33a of the guidepin 31 fastened onto the stay 33. Consequently, the load from the driverexerted to the steering wheel 16 is absorbed by the frictional expandingprocess of the slits 210a and 210b against the guide pin 31.

As well described hereinabove, in the first preferred embodiment,collision energy is substantially absorbed by expanding operation of theslits 210a and 210b. The energy absorbing cooperation can, therefore, bewell controlled by proper selections of a width, a length and a shapefor the slits 210a and 210b, by changing properly the thickness of theinner flanges 21a and 21b, and/or by adaption of rubber, synthetic resinand the like to cover the upper and lower ends of the slits 210a and210b and/or the guide pin 31. In absorbing the impact energy, theguiding operation of the guide pin 31 can deflect the steering columnstay 20 within a given range limited in a forward direction so as toprevent any side-movements of the steering column 10.

In the above description, the column stay 20 is fastened to theinstrument panel 80 by way of synthetic resin 24 which will disconnectthe column stay 20 from the instrument panel 80 with exersion of apredetermined or more forward impact load onto the column stay 20. Inthis instance, more specifically, the column stay 20 is fastened on thecapsule 23 fixedly secured on the instrument panel 80 through thesynthetic resin 24. The synthetic resin 24 may be replaced with ashearable pin 24 made of synthetic resin or metal as well shown in FIG.6-B.

A second preferred embodiment of the present invention is illustrated inFIGS. 7 and 8, wherein the energy absorbing device S comprises a columnstay 40 for supporting the column tube 12 substantially at a right angleagainst the instrument panel 80, a guide rod 42 connected to the columnstay 40 and an energy absorbing member 43 surrounding the guide rod 42.The energy absorbing member 43 functions to absorb forward impact forceloading to the column tube 12 in a predetermined or more value by way ofaxial and vertical deformation thereof when the column stay 40 movesforward by the load, and the guide rod 42 guides the column stay 40 inaccordance with the forward movement of the column stay 40.

The column stay 40 is formed in a substantial V-shape and provided atthe inside thereof with inner reinforcement flanges 41a and 41bprojecting downwardly and at the outer edge thereof with an outerreinforcement flange 41c jutting downwardly. The column stay 40 ismounted at one end thereof on the instrument panel 80 by the sameshearable connection as in the first preferred embodiment and the columntube 12 is supported at the other end of the column stay 40substantially at a right angle by the same construction as in the firstpreferred embodiment.

A pair of supporting metal pieces 45 is welded on the inside of theouter flange 41c of the column stay 40 to have a bolt 46 thereonthreaded into a nut 47 through a spring washer 48. The guide rod 42 isrotatably jointed with the bolt 46, and the top end of the guide rod 42is slidably supported in a supporting hole 44a drilled through a bracket44 with a L-shaped cross-section, the bracket 44 being fixed on theinstrument panel 80 together with the capsule 23. The guide rod 42 has athrough connecting hole 42a which has a spheric wall so that the guiderod 42 can be in connection with the bolt 46 rotatably in vertical andhorizontal directions.

The energy absorbing member 43 is made of steel meshes or stamped steelstrips formed or assembled in a zigzag configuration with spaced apartcreases or bends. The guide rod 42 is positioned axially in the centerof the energy absorbing member 43 the both ends of which are engagedrespectively with the inner face of the bracket 44 and the supportingmetal pieces 45. The longitudinal section of the energy absorbing member43 takes a waving shape so as to deform itself axially and vertically inresponse to a forward impact load given thereon in a value exceeding apredetermined one.

In occurrence of the collision of the vehicle, an impact load from thedriver is exerted onto the steering wheel 16 and the load is transmittedto the column stay 40 holding the steering column 10 in its normalposition. As in the case of the first preferred embodiment, the columnstay 40 is freed from the instrument panel 80 and moves forwardly. Asthe column stay 40 goes forwardly, the load is exerted on the energyabsorbing member 43. Sequently, the energy absorbing member 43 isallowed to buckle and the guide rod 42 proceeds forward to jut outthrough the bracket 44. Thus, the impact load given to the steeringwheel 16 is absorbed to protect the driver.

Since the collision energy absorbing operation is carried out in the wayas detailed hereinabove, it can well be controlled and adjusted byproper selections of a shape, a construction and/or materials for theenergy absorbing member 43. The energy absorbing operation can deflectthe steering column 10 within a certain given range limitted in aforward direction so as to prevent any side movements of the steeringcolumn 10.

A third preferred embodiment is referred to FIGS. 9 and 10. The energyabsorbing device S comprises a column stay 50 for supporting the columntube 12 substantially at a right angle against the instrument panel 80,an energy absorbing member 43 to be deformed for the energy absorbingoperation thereof when the column stay 50 makes a forward movement inresponse to a forward impact load given to the column tube 12 in a valueexceeding the predetermined one and a push rod 52 for deforming theenergy absorbing member 53 in the forward movement of the column stay50. As best shown in FIG. 9, the column stay 50 is formed in asubstantial trapezium and provided at its outer edge with areinforcement flange 51 projecting downwardly. This column stay 50 ismounted at one end thereof on the instrument panel 80 in the sameshearable connection as in the first preferred embodiment, and at theother end of the column stay 50, the column tube 12 is supportedsubstantially at a right angle in the same way as in the first preferredembodiment. The energy absorbing member 53 is a steel pressed piece witha substantially U-shaped cross-section and formed to have properlyforward and rearward curving portions. This energy absorbing member 53is welded on the bottom side of the instrument panel 80 and has anindent 53a at the center thereof to receive the top end of the push rod52 of which the base portion is rotatably connected with the column stay50. The push rod 52 is mounted on the column stay 50 in the same way asin the second preferred embodiment and no repetition is made here.

With the above-mentioned third preferred embodiment of the presentinvention, in the case of an unfortunate occurrence of a vehiclecollision, a forward impact load is exerted to the steering wheel 16through the driver. The load is then transmitted to the column stay 50holding the steering column 10 approximately at a right angle. Throughthe same operation as in the first preferred embodiment, the column stay50 is freed from the instrument panel 80 and moves forward. Inaccordance with the forward movement of the column stay 50 the push rod52 integrally interlocked with the column stay 50 urges the energyabsorbing member 53 to deform it for energy absorbing operation.

It should now be very clear that the impact energy absorbing operationcan well and easily be controlled and adjusted by proper selections of athickness, a number of the curved portions and a shape of thecross-section of the energy absorbing member 53. In the energy absorbingoperation, the operation of the push rod 52 can deflect the steeringcolumn 10 in a certain given range limited in a forward direction so asto prevent any side movements of the steering column 10.

Now reference is made to FIGS. 12 and 13 for a fourth preferredembodiment of the present invention. The energy absorbing device Scomprises a column stay 60 for supporting the column tube 12substantially at a right angle against the instrument panel 80, anenergy absorbing member 64 to buckle for its impact energy absorbingoperation when the column stay 60 moves forward by a forward impact loadgiven to the column tube 12 in a value exceeding a predetermined one anda push rod 63 to buckle the energy absorbing member 64 in response tothe forward movement of the column stay 60. The column stay 60 is, asbest shown in FIG. 12, formed approximately in a V-shape and provided atits inner edge with inner reinforcement flanges 61, 61 and at its outeredge with an outer reinforcement flange 62, the flanges 61, 61 and 62being projected downwardly. This column stay 60 is firmly mounted at itsone end on the instrument panel 80 in the same shearable connection asin the case of the first preferred embodiment. At the other end of thecolumn stay 60, the column tube 12 is supported substantially at a rightangle in the same way as in the first preferred embodiment.

The energy absorbing member 64 is welded on the bracket 32 fixed on theinstrument panel 80 together with the capsule 23 as explained in detailin the first preferred embodiment. The energy absorbing member 64 has asubstantial L-shape (or U-shape) in section and is provided at a portionthereof with a barring portion 64a to have the top end of the push rod63 inserted therein. The barring portion 64a may be prepared in a pluralnumber along the axis of the push rod 63 and/or covered with syntheticresin 64b as shown in FIG. 12-B. The push rod 63 is tapered in sectionto be with larger diameters torward its base end and loosely andslidably engaged with the barring portion 64a of the energy absorbingmember 64. In this embodiment, too, the same mounting construction ofthe push rod 63 to the column stay 60 is applied as in the secondpreferred embodiment.

A forward impact load produced by a vehicle collision is exerted to thecolumn stay 60 by way of the driver, the steering wheel 16 and thesteering column 10. Through the same process as in the first preferredembodiment, the shearable connection of the column stay 60 with theinstrument panel 80 is broken and the column stay 60 moves forward.Sequently, the push rod 63 integrally interlocked with the column stay60 is pushed forward to expand, in turn, the barring portion 64a of theenergy absorbing member 64 by way of its tapered periphery. Thus, theforward impact energy is absorbed to protect the driver.

The impact energy absorbing operation can well be controlled andadjusted by proper selections of a number, a size and materials of thebarring portion 64a and also by changes of the tapering degree of thepush rod 63. In the energy absorbing operation, the steering column 10can be tilted in a certain given range by operation of the push rod 63.

A fifth preferred embodiment of the present invention is referred toFIGS. 14 and 15. The energy absorbing device S comprises a column stay70 for supporting the column tube 12 substantially at a right angle.proper wave shapes are applied for the sides and cross-section of thecolumn stay 70 which is a pressed work out of steel sheet. Slits 71a and71b are transversely provided in the indented portions of the wavedsurface of the column stay 70. A flange 70a juts down from the outeredge of the column stay 70 one end of which is firmly secured on theinstrument panel 80 at two or more portions by fastening bolts 73threaded through spring washers 74 into nuts 72 welded on the lowerinner face of the instrument panel 80. At the other end of the columnstay 70, the column tube 12 is supported substantially at a right angleas in the case of the first preferred embodiment.

A forward impact load from the driver in occurrence of the vehiclecollision is transmitted to the collumn stay 70 through the driver, thesteering wheel 16, the steering column 10 and the column stay 70. Thetransmitted load compresses the column stay 70 and, thus, the waveportions of the column stay 70 buckles to absorb the energy not to giveto the driver sudden reaction force.

The energy absorbing operation is well controlled land adjusted byproper selections of a thickness, a wave shape and pitch, and materialsof the column stay 70 and of shapes and sizes for the slits 71a and 71b.In the energy absorbing operation, the steering column 10 can deflectedin a certain given range.

FIGS. 16 and 17 illustrate a sixth preferred embodiment of the presentinvention. The energy absorbing device S comprises a column stay 90 tosupport the collumn tube 12 substantially at a right angle against theinstrument panel 80, a piston 96 integrally secured on the column stay90 and an energy absorbing bag 94 for absorbing a forward impact energyas it is compressed by the piston 96 in the forward movement of columnstay 90 when the column tube 12 is given a forward impact load exceedinga predetermined value. The column stay 90 is formed to have aconfiguration of an approximate trapezium as well as seen in FIG. 16. Areinforcement flange 91 is provided to project downwardly from the outeredge of the column stay 90 one end of which is firmly secured on theinstrument panel 80 as done in the first preferred embodiment. Thecolumn tube 12 is supported as done in the first preferred embodiment atthe other end of the column stay 90. The energy absorbing bag 94 is madeof such flexible materials as rubber, synthetic resin and the like andhas at least one hole 95a at an adequate portion thereof. The energyabsorbing bag 94 is filled with hydraulic or pneumatic fluid and thehole 95a is sealed with a sealing member 95b. A supporting case 93 iswelded at the center portion of the bottom face of a bracket 92 securedon the instrument panel 80, the supporting case 93 being open at oneside to receive the energy absorbing bag 94 therein. The piston 96 hasits base portion welded on a bracket 98 which is welded on the innersurface of the flange 91 of the column stay 90, the piston 96 beingpositioned to project substantially at a right angle toward the columntube 12. A place piece 97 is provided at the top end of the piston 96and in touch with a side face of the energy absorbing bag 94.

In occurrence of a vehicle collision, the column stay 90 receives aforward impact load transmitted thereto through the driver, the steeringwheel 16 and steering column 10. The same process detailed in the firstpreferred embodiment disconnects the column stay 90 from the instrumentpanel 80 and the column stay 90 moves forward. This forward movement ofthe column stay 90 pushes forwardly the piston 96 integrally interlockedwith the column stay 90. The plate piece 97 of the piston 96 compressesthe energy absorbing bag 94 to increase the hydraulic or pneumaticpressure inside the energy absorbing bag 94. When the pressure reaches acertain given value, the sealing member 95b is blown off from the hole95a through which, in turn, the fluid escapes to absorb the impactforce.

The energy absorbing operation can easily be controlled and adjusted byproper selections of a size and materials of the bag 94 and/or a sizeand a number of the hole 95a. In the energy absorbing operation, thesteering column 10 can be deflected in a certain predetermined range.

The safety features of the present invention are furthermorecharacterized with the following construction of a steering wheeldevice. Reference is now made to FIGS. 18 to 23, inclusive, whereindisclosed is the steering wheel 16 which includes two spokes 102, 102having a U-shaped cross section. The spokes 102, 102 extend integrallyalong the radius of the steering wheel 16 and the base ends of thespokes 102, 102 are welded on the periphery of a supporting member 103.The supporting member 103 is a ring member with an arc cross section andas well shown in FIGS. 21 and 22, a concaved spheric wall 131 is formedon the inner circumference of the supporting member 103. A recess 132 iscut off from the upper portion of the supporting member 103. A hub 104has a taper hole 141 and a serration 142 drilled at the center portionthereof and a tapered portion 161 and a serration 162 at the top end ofthe steering shaft 11 are engaged with the taper hole 141 and theserration 142. A threaded portion 163 bossed from the steering shaft 11into a cavity 110 of the hub 104 is fastened by a lock nut 112 through aspring washer 111 so that the hub 104 is firmly secured on the top endof the steering shaft 11 and never allowed to rotate. The periphery ofthe hub 104 is designed to have a convexed spheric wall 143 whichcorresponds with the concaved spheric wall 131 of the supporting member103. The supporting member 103 is coupled with the hub 104 to berotatable by way of the corresponding spheric walls 131 and 143. Aplurality of through holes 133 are radially drilled on the supportingmember 103 (in this embodiment four through holes) and correspondingly aplurality of holes 144 are also provided on the spheric periphery 143 ofthe hub 104. The supporting member 103 and the hub 104 are integrallysecured by shearable pins 105 inserted into the holes 133 and 144. Theshearable pins 105 are made of synthetic resin or metal. The supportingmember 103 and the hub 104 are molded correspondingly with the syntheticresin 120 covering the steering wheel 16 and the spokes 102, 102. Andthe supporting member 103 is further prohibited to rotate against thehub 104 by way of the synthetic resin 120 molded around the shoulders103a thereof. The recess 132 of the supporting member 103 is for easycoupling of the hub 104 into the supporting member 103 and, uponcompletion of the assembling work of the hub 104 to the supportingmember 103, is mounted with a filling member 109 and covered up with thesynthetic resin 120 integrally molded. Indicated with a referencenumeral 107 is a horn button positioned at the center of the steeringwheel 16.

In occurrence of a vehicle collision, a forward impact load from thedriver is exerted to the steering wheel 16 at a limited portion. Whenthis impact load exceeds a predetermined value, the shearable pins 105are sheared off to disconnect the supporting member 103 from the hub104. The synthetic resin 120 around the supporting member 103 is brokenand the supporting member 103 makes frictional rotation along thespheric periphery 143 of the hub 104 in response to the direction of theload force. This deflects the steering wheel 16 as shown in FIG. 19. Thesupporting member 103 never comes off from the hub 104 in the shockabsorbing rotation. It is now clear that in the vehicle collision, theload collectively given to a limited portion of the steering wheel 16 isturned to be received by the whole steering wheel 16 to soften theimpact force given to the driver.

The impact load absorbing operation can well be controlled by the properselections of a nature and a shape of the shearable pins 105 andconnecting force between he supporting member 103 with the syntheticresin 120.

Another embodiment is disclosed in FIG. 24-30, inclusive, wherein thereis shown a spoke 201 radially extending from a steering wheel (notshown). The base end of the spoke 201 is welded on the annular peripheryof an upper hub member 202. An annular lower hub member 204 secured onthe steering shaft 11 is connected with the upper hub member 202 by wayof a cylindrical energy absorbing member 203 the top end of which iswelded on the neck of the upper hub member 202. The spoke 201, the upperhub member 202, the energy absorbing member 203 and the lower hub member204 are molded all over with synthetic resin 205 to form the wholesteering wheel.

The energy absorbing member 203 is formed in a cylindrical shape out ofsheet metal with a selected thickness, as well illustrated in FIG. 25. Aplurality of oblong cut-out holes 231 are provided axially on theperiphery of the energy absorbing member 203. The strength of the energyabsorbing member 203 can well be adjusted by proper selections of asize, shape, and number of the holes 231 and/or a thickness of sheetmetal. When molded integrally with the synthetic resin 205, the energyabsorbing member 203 has its holes 231 filled with the synthetic resin205. Serration 241 and a taper hole 242 are provided respectively at theupper center portion and at the lower center portion of the lower hubmember 204. Serration 261 and a tapered portion 262 provided at the topend of the steering shaft 11 are engaged with the serration 241 and thetaper hole 242 which are firmly secured on the steering shaft 11 by anut 211 threaded through a spring washer 212 onto a threaded portion 263jutting up into a cavity formed within the energy absorbing member 203.A horn button 208 is made of elastic synthetic resin, for instance,uretan rubber, integrally with a base plate 281 and assembled by a screw283 through a coil spring 210 and a ring 213 on a holding member 209 ofa cup shape secured on a shoulder of the inner circumference of theupper hub member 202.

In occurrence of a vehicle collision, a forward impact load from thedriver is exerted on the steering wheel 16 at a limited portion. Thetransmitted load compresses and deforms the energy absorbing member 203and sequently, the synthetic resin 205 is broken. Thus, the steeringwheel 16 is turned in response with the load operating direction.Therefore, although a portion of the driver's body is impactly struck toa limited portion of the wheel, the impact load is received by the wholewheel 16 so as to protect the driver.

In the above embodiments, the strength of the energy absorbing member203 is to be adjusted by a shape, size and number of the holes 231. Theadjustment can be made as well by changes of the shape of an indent 231'provided on a cylindrical energy absorbing member 203', shown in FIG.27, to replace the energy absorbing member 203. The energy absorbingmember 203 can also be replaced with another 203", shown in FIGS. 29 and30, which has a plurality of oblong holes 231" cut off therefrom, theoblong holes 231" being horizontally positioned zig-zag to each other.The strength adjustment of the energy absorbing member 203" can be madeby good selections of a shape, size and number of the holes 231" and/ora thickness of the energy absorbing member 203" itself. With thesteering wheel 16 adopting the energy absorbing member 203", the forwardimpact load exerted thereto from any direction can well be absorbed andsoftened by buckling deformation of the energy absorbing member 203".

Having now fully set forth both structure and operation of preferredembodiments of the concept underlying the pressent invention, variousother embodiments as well as certain variations and modifications of theembodiments herein shown and described will obviously occur to thoseskilled in the art upon becoming familiar with said underlying concept.It is to be understood, therefore, that within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallyset forth herein.

What is claimed is:
 1. In a vehicle having a steering column assembly,including a steering shaft, steering gear means, means for flexiblycoupling said shaft vertically to said gear means for forward pivotalmovement of said shaft, and a column tube having said steering shaftjournalled therein and permitting said forward pivotal movement of saidshaft, apparatus for supporting said steering column assembly,comprising: a support structure releasably mounted at its front part toa portion of the instrument panel of said vehicle and secured at itsrear part to said steering column tube, said steering asssembly supportstructure including an impact energy absorbing member having adeformable portion to be plastically expanded outwardly and means forexpanding said deformable portion of said energy absorbing member duringthe forward displacement of said support structure by secondary impactenergy exerted thereon from said steering column.
 2. A steering columnsupporting apparatus as claimed in claim 1, wherein said steeringassembly support structure includes a column stay provided with a pairof longitudinal reinforcement flanges extended downwardly therefrom andpositioned in parallel to each other, means securing the rear endportion of said column stay on said steering column, means releasablymounting the front end portion of said column stay on a portion of theinstrument panel of the vehicle, a bracket member mounted on saidinstrument panel transverse to the front portion of said column stay,and a guide pin transversely supported by said bracket member andprovided with a pair of guiding portions at the both ends thereof, saidguiding portions being slidably engaged with the front portions of apair of longitudinal slots provided on said flanges respectively,whereby said guide pin plastically expands said slots of said flanges byimpact energy exerted on said column stay from said steering column andguides the forward displacement of said column stay.
 3. A steeringcolumn supporting apparatus as claimed in claim 7, wherein said slots ofsaid flanges are tapered towards the rear portions of said flanges.
 4. Asteering column supporting apparatus as claimed in claim 2, wherein saidslots of said flanges are straight ones.
 5. A steering column supportingapparatus as claimed in claim 2, wherein said guiding portions of saidguide pin are grooves.
 6. A steering column supporting apparatus asclaimed in claim 2, wherein a pair of pads made of synthetic resin arerespectively disposed between said guiding portions of said guide pinand said slots of said flanges.
 7. A steering column supportingapparatus as claimed in claim 2, wherein said means for releasablymounting the front end portion of said column stay on the portion ofsaid instrument panel comprises a pair of capsules secured under saidinstrument panel to receive respectively the both sides of the frontportion of said stay and a pair of securing elements to adhere on theinteriors of said capsules for receiving said stay.
 8. A steering columnsupporting apparatus as claimed in claim 2, wherein said means forreleasably mounting the front end of said column stay on the portion ofsaid instrument panel comprises a pair of capsules secured under saidinstrument panel of the vehicle to receive respectively the both sidesof the front portion of said column stay and a pair of shearable pinsholding said both sides of said column stay within said capsules.
 9. Asteering column supporting apparatus as claimed in claim 1, wherein saidsteering assembly support structure includes a column stay releasablymounted at its front end portion on a portion of the instrument panel ofthe vehicle and secured at its rear end portion on said steering column,a guide rod positioned longitudinally along said column stay with itsrear end connected to the rear portion of said stay and tapered towardsits front end, and a bracket member securely mounted on said instrumentpanel and provided with a barring portion to receive slidably the frontend of said guide rod, whereby said guide rod plastically deforms thebarring portion of said bracket member to absorb the forwarddisplacement of said column stay when an inpact force is exerted ontothe upper portion of said steering column.
 10. A steering columnsupporting apparatus as claimed in claim 9, wherein a pad member isdisposed between said barring portion of said bracket member and saidguide rod.